TY - JOUR
T1 - Prognostic significance of circadian variability of RR and QT intervals and QT dynamicity in patients with chronic heart failure
AU - Watanabe, Eiichi
AU - Arakawa, Tomoharu
AU - Uchiyama, Tatsushi
AU - Tong, Mao Qing
AU - Yasui, Kenji
AU - Takeuchi, Hiroshi
AU - Terasawa, Toshiaki
AU - Kodama, Itsuo
AU - Hishida, Hitoshi
PY - 2007/8
Y1 - 2007/8
N2 - Background: In patients with chronic heart failure (CHF), circadian variability of RR and QT intervals may be altered because of neurohumoral activation and functional and structural remodeling of the heart. Objective: The aim of this study was to evaluate the prognostic significance of circadian variability of the RR and QT intervals and QT dynamicity (QT/RR slope) in CHF patients. Methods: We prospectively enrolled 121 patients with stable CHF in sinus rhythm (age 67 ± 14 years, mean ± SD; range 34 to 87 years). The RR, QT, and rate-corrected QT (QTc) intervals and the QT/RR slope measured from 24-hour Holter electrocardiogram were fitted by cosine curves. Results: During the follow-up period of 34 ± 17 months, 40 (33%) patients died of cardiac causes, 10 of which were sudden. All patients showed significant circadian rhythms in the RR, QT, and QTc intervals and the QT/RR slope by cosine-curve fitting. In addition to the expected higher heart rate, longer QT interval, and steeper QT/RR slope, we found that patient who died of cardiac causes had reduced circadian variability of QT interval (10 ± 10 ms vs 21 ± 13 ms) and a later maximum RR interval (4.1 ± 0.9 AM vs 2.3 ± 2.1 AM) compared with survivors, among many other statistically significant circadian parameter differences. These 2 parameters were independent predictors of cardiac death in multivariate Cox proportional hazards regression analysis. Conclusion: Circadian variability analyses of Holter-derived RR and QT intervals may provide prognostic information beyond that provided by 24-hour averages of these parameters.
AB - Background: In patients with chronic heart failure (CHF), circadian variability of RR and QT intervals may be altered because of neurohumoral activation and functional and structural remodeling of the heart. Objective: The aim of this study was to evaluate the prognostic significance of circadian variability of the RR and QT intervals and QT dynamicity (QT/RR slope) in CHF patients. Methods: We prospectively enrolled 121 patients with stable CHF in sinus rhythm (age 67 ± 14 years, mean ± SD; range 34 to 87 years). The RR, QT, and rate-corrected QT (QTc) intervals and the QT/RR slope measured from 24-hour Holter electrocardiogram were fitted by cosine curves. Results: During the follow-up period of 34 ± 17 months, 40 (33%) patients died of cardiac causes, 10 of which were sudden. All patients showed significant circadian rhythms in the RR, QT, and QTc intervals and the QT/RR slope by cosine-curve fitting. In addition to the expected higher heart rate, longer QT interval, and steeper QT/RR slope, we found that patient who died of cardiac causes had reduced circadian variability of QT interval (10 ± 10 ms vs 21 ± 13 ms) and a later maximum RR interval (4.1 ± 0.9 AM vs 2.3 ± 2.1 AM) compared with survivors, among many other statistically significant circadian parameter differences. These 2 parameters were independent predictors of cardiac death in multivariate Cox proportional hazards regression analysis. Conclusion: Circadian variability analyses of Holter-derived RR and QT intervals may provide prognostic information beyond that provided by 24-hour averages of these parameters.
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U2 - 10.1016/j.hrthm.2007.04.019
DO - 10.1016/j.hrthm.2007.04.019
M3 - Article
C2 - 17675071
AN - SCOPUS:34547403306
SN - 1547-5271
VL - 4
SP - 999
EP - 1005
JO - Heart Rhythm
JF - Heart Rhythm
IS - 8
ER -